I don't know if this is new with patch 9, but I've done maybe 8 playthroughs of EA and this is the first time it's happened, and it happened twice in a row.
Both times, after entering the cave through the stone door and clicking over in the area where Zevlor is, Lae''zal just slipped off the edge of the pit and died.
It didn't happen on the third reload, thankfully.
